Dithiocarbonic acid esters and production



United States Patent DITHIOCARBONIC ACID ESTERS AND PRODUCTION Gerhard Schrader, Opladen, Germany, assignor to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application January 31, 1956 Serial No. 562,597

Claims priority, application Germany February 10, 1955 8 Claims. (Cl. 260-455) This invention relates to alkyland aryl-thiomethyldithiocarbonic acid esters of the general formula S RS-OHzS-C i-OR wherein R and R stand for a member selected from the group consisting of aliphatic and aromatic radicals.

By the action of hydrochloric acid on paraformaldehyde in the presence of an aliphatic or aromatic mercaptan, reactive a-chloromethyl-alkylor -aryl-thioethers are found.

It is an object of this invention to provide a process for the production of dithiocarbonic acid esters from alkylor aryl-a-chloromethyl-thioethers.

It is another object of this invention to provide new dithiocarbonic acid esters having good insecticidal properties.

Further objects will become apparent as the following description proceeds.

In accordance with the invention it has now been found that by reacting reactive u-chloromethyl-thioethers with the alkali metal salts of dithiocarbonic acids stable and novel dithiocarbonic acid esters are formed which are distinguished by a remarkable insecticidal action whilst having only a small toxic action on Warm-blooded animals.

Suitable a-chloromethyl thioethers are alkyl or aryl thioethers, such as methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, decyl, dodecyl, stearyl, phenyl, tolyl, benzyl, chlorophenyl, chlorobenzyl, dichlorobenzyl, pyridyl, and quinonyl thioethers. As dithiocarbonic acid esters there may be used the esters having as ester radical the alkyl or aryl thioether radicals aforementioned. Suitable salts of these dithiocarbonic acid esters are their alkali, alkaline-earth metal and ammonium salts; preferably the sodium and potassium salts thereof are used.

The reaction is expediently carried out in a suitable solvent, such as alcohols, hydrocarbons, acetone, ethyl, methyl ketone, and cyclohexanone. Particularly suitable solvents are ketones which readily dissolve the alkali metal salts of the dithiocarbonic acids. The reaction is carried out at temperatures of between 0 and 150 C. preferably between and 80 C.

The new products are strongly yellow-colored oils which may be distilled in vacuo without decomposition.

The following examples are given for the purpose of illustrating the new process but are not intended to limit same in any way.

Example 1 grams of u-chloromethyl-ethyl sulphide are added dropwise with stirring to a suspension of 48.6 grams of potassium ethyl Xanthogenate in 200 millilitres of methylethyl ketone at 35-40 C. After the reaction has subsided, the reaction product thus obtained is poured into much water, the separated oil is taken up in chloroform, the chloroform solution is washed again with water, and

the temperature being maintained for a further hour 60 C. After usual working up 120 grams of the new then dried and fractionated. 50 grams of the new ester are obtained representing a light yellow water-insoluble oil, B. P. 100 C./1 mm. Hg. An emulsion of 0.1% of the ester killed 100% of tested red spiders.

Example 2 81 grams of potassium ethyl Xanthogenate are suspended in 400 millilitres of methylethylketone. grams of a-chloromethyl-n-butylthioether (B. P. 60-61 C./ 14 mm. Hg) are added with stirring to the suspension at 45 C. After usual Working up, grams of the new ester are obtained having a boiling point of 125 C. at a pressure 0f2 mm. Hg. A 0.1% emulsion of the ester kills of the tested red spiders.

Example 3 i CaH13S-OH2S-CO C2115 81 grams of potassium ethyl xanthogenate are suspended in 400 millilitres of methylethylketone. 84 grams of a-chloromethyl-n-hexylsulphide (B. P. 66 C./2 mm. Hg) are added with stirring to the suspension at 60 C ester are obtained mm. Hg.

having a boiling point of 137 C./2

Example 4 Example 5 48 grams of potassium ethyl xanthogenate are suspended in 300 millilitres of methylethylketone. 46 grams of a-chloro-methyl-phenyl sulphide (B. P. 7274 C./1 mm. Hg) are added with stirring to the suspension at 75 C. The temperature is maintained at 75 C. for a further hour. After usual working up 60 grams of the new ester having a boiling point of C./ 0.05 mm. Hg are obtained.

A 0.01% aqueous solution of the new ester is sufiicient to kill aphides.

Example 6 48 grams of potassium ethyl Xanthogenate are suspended in 250 millilitres of methylethylketone. To this suspension there are added with stirring 46 grams of a-chloromethyl-p-cresylthioether (B. P. 88 C./1 mm. Hg) at 75 C. The temperature is kept at 75 C. for a further hour. After usual working up 60 grams of the new ester are obtained of B. P. of C./2 mm. Hg.

Patented June 17, 1958 2,889,661 r a 3 4 I claim: a 6. The dithiocarbonic acid ester of the formula 1. Alkyland aryl-thiomethyl-dithiocarbonic acid esters s of the general formula lg s P; 5 7. The dithiocarbonic acid ester of the formula s wherein R stands for a member selected from the group ll consisting of an alkyl, a phenyl, an alkaryl and an aralkyl S CH S C O radical and R is a lower alkyl radical.

8. Process for the production of alkyl and aryl thio- The dlthlocarbomc and ester of the formula methyl dithiocarbonic acid esters of the general formula II T l CzHs -CHr-S-C-OCzHs RSCH -SCOR' The dithiocarbonic acid ester of the formula which comprises reacting a salt of a dithiocarhonic acid ester having the formula ll V i C4HoS-'CHz-SCOCzH ROCSX i with an a-chloromethyl thioether having the formula The dlthlocarbom? and ester of the formula CICH SR in an inert liquid organic solvent wherein R stands for a member of the group consisting of an alkyl, a phenyl, an alkaryl and an aralkyl radical, X is a radical Cans CHrs b OCZH selected from the group consisting of alkali metal, alkali 5. The dithiocarbonic acid ester of the formula Carib metal and ammonium, and is a lower alkyl radical.

References Cited in the file of this patent UNITED STATES PATENTS 2,323,797 Cook July 6, 1943 

1. ALKYL- AND ARLY-THIOMETHYL-DITHIOCARBONIC ACID ESTERS OF THE GENERAL FORMULA 